The most recent version of LaTeX is nominally dated 2015/10/01 (it may additionally have a patch-level associated with it).
Due to the small number of changes these days new releases will appear at irregular intervals, at most once a year. If you are in need of some immediate bug fix you may try the svn version of the source code.
Starting with the 2015/01/01 release we provide a "latexrelease" package that allows you to emulate older (or newer) versions of the format without regenerating it from scratch; see ltnews22 for further details.
Note: ltnews18 doesn't exist. By mistake we incremented the issue number twice moving directly from 17 to 19.
Release dateNews issue (PDF)2015/10/01LaTeX2e News Issue 23
2015/01/01LaTeX2e News Issue 22
2014/05/01LaTeX2e News Issue 21
2011/06/27LaTeX2e News Issue 20
2009/10/15LaTeX2e News Issue 19
2005/12/01LaTeX2e News Issue 17
2003/12/01LaTeX2e News Issue 16
2003/12/01LaTeX2e News Issue 15
2001/06/01LaTeX2e News Issue 14
2000/06/01LaTeX2e News Issue 13
1999/12/01LaTeX2e News Issue 12
1999/06/01LaTeX2e News Issue 11
1998/12/01LaTeX2e News Issue 10
1998/06/01LaTeX2e News Issue 09
1997/12/01LaTeX2e News Issue 08
1997/06/01LaTeX2e News Issue 07
1996/12/01LaTeX2e News Issue 06
1996/06/01LaTeX2e News Issue 05
1995/12/01LaTeX2e News Issue 04
1995/06/01LaTeX2e News Issue 03
1994/12/01LaTeX2e News Issue 02
1994/06/01LaTeX2e News Issue 01